Cost-of-living impacts commercial viabilityOf course, how much you need to "make a living" will depend on where you live. It's no accident that urban farming is taking off in distressed cities like Detroit, but what about high-cost-of-living communities like LA?

Scott Henley, who lives in Pasadena, Los Angeles, decided to see if he and his family could grow enough in his suburban backyard to avoid the need for one parent to go to work. Using aquaponics, Henley is growing tilapia, water cress, salad crops and vegetables, and he's selling them to local restaurants and at the farmers' market. Urban farmers need mutual supportWhether or not you can make enough to avoid a job, that's still an open question. Henley says he is covering his costs and making a modest amount of surplus, but he's hopeful that he can improve on these economics as the tilapia operation matures and as more urban farmers begin to collaborate on ways to cut costs and support each others' efforts. Either way, he laughs, he's really enjoying himself as he struggles to get by.

The economics of all this are interesting in and of themselves. But aquaponics geeks might also want to watch the video to see how Henley is dealing with the challenge of keeping water to temperature. He's soon going to be converting his tilapia production to pure aquaculture, and use minnows instead for the aquaponics - which then become a feedstock for the tilapia.